Electric Crane Grab

Electric Crane Grab

According to the driving mode, it can be divided into hydraulic grab and mechanical grab.
1、 Hydraulic grab
hydraulic grab
The hydraulic grab is equipped with an opening and closing structure, which is generally driven by a hydraulic cylinder. The hydraulic grab composed of multiple jaw plates is also called a hydraulic claw. Hydraulic grab is widely used in hydraulic special equipment, such as hydraulic excavator and hydraulic lifting tower.
The hydraulic grab is a kind of hydraulic structure product, which is composed of hydraulic oil cylinder, bucket (jaw plate), connecting column, bucket ear plate, bucket ear sleeve, bucket tooth, tooth seat and other parts. Therefore, welding is the key manufacturing process of the hydraulic grab, and the welding quality directly affects the structural strength and service life of the hydraulic grab. In addition, the hydraulic cylinder is also a key driving component.
Hydraulic grab is a special industry equipment accessory, which requires special equipment to operate with high efficiency and quality, such as: CNC plasma cutting machine, groove milling machine, plate bending machine, welding positioner, boring machine, hydraulic test bench, etc.
The special hydraulic grab for excavator is divided into two types: slewing and non slewing. The grab without slewing adopts the oil circuit of the bucket cylinder of the excavator, without adding additional hydraulic valve block and pipeline; A set of hydraulic valve block and pipeline shall be added to the bucket with rotation for control.
Application of hydraulic grab for excavator:
1. Foundation pit excavation, deep pit excavation and loading of mud, sand, coal and gravel for building foundation.
2. Especially suitable for excavation and loading on one side of a trench or restricted space.
3. It is applicable to the loading and unloading of ships, trains and automobiles.
2、 Mechanical grab
The mechanical grab is not equipped with an opening and closing structure, and is usually driven by the external force of the rope or connecting rod. According to the operating characteristics, it can be divided into double rope grab and single rope grab, and the commonly used double rope grab.
The mechanical grab double rope grab has a support rope and an opening and closing rope, which are respectively wound on the drums of the support mechanism and the opening and closing mechanism. Fig. 1 shows the working process of the double rope grab: a means that the support rope and the opening and closing rope descend at the same time, and the bucket mouth is opened to insert the material pile. B is to tighten the opening and closing rope, close the jaw plate and grasp the material. C is that the support rope and the opening and closing rope rise simultaneously after the grab is closed. D. to keep the support rope stationary, the opening and closing rope is lowered, the bucket mouth is opened and the material is unloaded. The double rope grab is reliable, easy to operate, high productivity and widely used. After using two groups of double ropes, it becomes a four rope grab, and the working process is the same as that of the double rope grab.
The single rope grab support rope and the opening and closing rope use the same wire rope. The special locking device enables the steel wire rope to support and open and close in turn. The winding mechanism of the single rope grab is relatively simple, but its productivity is low, and it is rarely used in a large number of loading and unloading operations.
According to the bulk density of the materials to be gripped, the grab can be divided into three categories: light (such as gripping grain), medium (such as gripping gravel) and heavy (such as gripping iron ore); According to the number of jaw plates, it is divided into double jaw plate grab and multi jaw plate grab. The commonly used is double jaw plate grab. For large ores, iron scraps and scrap steel, it is advisable to use a multi jaw grab, because it has the characteristics of multi claws and sharp cuts, is easy to insert into the pile, and can obtain a good grasping effect. There is also a scissor type grab which imitates the scissor structure principle. Its grasping force can gradually increase with the closure of the jaw plate and reach the peak at the end of closure; The opening of the bucket mouth and the area covered by the material are also larger than those of the general grab bucket, which improves the gripping ability and is conducive to cleaning the stock yard and the cabin. However, for large materials, the initial gripping force is small and the effect is poor.